Dental matrix retainer



July 18, 1944, J.'D. MORRISON $353,747

DENTAL MATRIX RETAINlfIR Filed Aug. 6, 1942 mzam Patented July 18, 1944 orr cr.

. 2,353,747 V'DENTAL MATRIX RETAINER James D. Morrison, Medicine Hat, Alberta,

. Canada 1 Application August 6, 1942, Serial No. 453,891

Claims.

has been diflicult to eiiect a proper retention of the matrix band upon atooth where considerable decay has occurred, particularly around the vertical walls of a tooth, since actual contact suriace between the tooth and band has been reduced to a large extent.

It is therefore an object. of the invention to provide a novel construction of matrix and band in which a uniform tension upon the band is effected firmly holding the band snugly around all surfaces of a tooth.

It is also an object of the invention to afiord a matrix holder in which a simplified construction is provided for holding the band upon a pair of opposite movable blocks, the holding means being readily releasable from the band so that the latter may be removed'laterally from a tooth, as 1 will be required in many cases, or where necessary, the band may, be removed in a direction a longitudinally of the tooth- More-specifically. it is an object of the invention to provide'a novel construction of matrix holder in which a rigid block embodies a guide 1 channel cooperable with a movable block constructed to traverse the channel upon actuation of an operating worm shaft, the interengagement between the channel and movable block being such that the movable block will partake of a smooth motion, free of any binding tendency upon the worm shaft; and to provide each of the blocks with a clevisdevice for attachment of respective ends of a matrix band.

Additional objects, advantages and features of invention will be apparent from the following description considered in conjunction with the accompanying drawing, wherein Figure 1 is a top plan view of the matrix retainer and band applied to a tooth.

Figure 2 is an edge view of the matrix retainer.

Figure 3 is a longitudinal sectional view thereof.

Figure 4 is an enlarged cross section through the matrix retainer.

Figure 5 is an end view thereof.

Figure 6 is a perspective view of the retainer.

Figure 7 is a perspective view of the matrix band in position to receive the retainer.

Figure 8 is an enlarged detail illustrating the operative position of the band securing means.

There is illustrated a matrix holder generally indicated by the reference character it! which consists of an elongated channel body member I I having parallel side walls l2 and a smooth rounded base wall I3, so that angular portions are avoided which might be uncomfortable to a patient when in use. The upper ends of the walls 12 are inwardly turned in the direction of the longitudinal axis of the body forming opposed flanges l4 each of which stop a substantial distance outwardly from said axis for a purpose as will presently appear. Integrally formed with the body there is a block member l5 of a height projecting beyond the upper edges of the flanges l4. Formed in the block I5 there is a threaded opening 16 extended in a plane incident with the channel of the body member, and spaced so that the flanges l4 extend approximately in the medial center of the opening l6. Within the channel of the body member Ill there is a movable block H, the base portion of which is shaped to correspond to the bottom wall l2 for snug yet slidable engagement therein. In order to accommodate the opposed flanges i l of the channel member, the block is formed with a slot i8 upon each side extending the full length of the block, adapted to receive respective flanges therein. By this construction, it will be apparent that the block I! may partake of sliding movement along the channel without liability of vertical or lateral movement. The block 11 is also formed with a threaded opening l9 aligned with the opening l6 and through these openings there is a worm shaft 26) of a length greater than that of the body H, the end 2| of which is provided with a squared end 22 for reception of a manipulating handle 23 for rotating the shaft 20 to efiect simultaneous movement of the body member and the movable block.

The shaft 20 is provided with oppositely threaded portions 24 and 25 and preferably the portion 24 is left-handed and the latter righthanded so that a rotation of the shaft 20 in a clockwise direction will tend to separate the blocks and eifect the tightening of a 'band engaged with respective blocks.

The blocks I5 and l! are each provided with respective pins 26 secured in the upper faces thereof, the pins being inclined from the vertical axis of the blocks in opposite directions. A loop device 21 is swingably mounted upon each block cooperable with respective pins for securing the ends of the matrix band as will be described hereinafter. In the present instance, the loops are formed from a suitable gauge of steel wire bent to form a bight portion 28 and spaced leg members 29, the terminal ends of which are bent inwardly to form pivots 3G. The pivots 3B are mounted in suitable apertures formed in the sides of the blocks. The pivots are positioned slightly oil center with respect to the point of mounting of the pins 26 so that under clamping action of the matrix holder a binding action will occur betweenv the bight portions 28 and the pins 26, as will be described.

Attention is now invited to Figure '7 of the drawing wherein the matrix band is shown, and cone.

sists of a main body 3| of a width and length required for its application upon a given tooth. The body 3| is provided with terminal ends 32 and 33 of greatly reduced widths as clearly shown, the end 32 being formed as a continuation of the lower end of the body, while the-end 33 is spaced slightly upward from said edge so as to align with a slot 34 at the opposite side of the body. It will be noted that the terminal ends are thus in a cross relationship, as shown in Figures 1 and 7. Each end 32 and 33 is provided with an aperture 35 for reception of respective pins'ZB-Of the matrix. It is a known fact that a tooth is more or less bell shaped and of varying diameters and heights and for this reason the band is cut to fit each individual tooth, the bell-shape being provided for by cutting the band longitudinally at its base in an arcuate path. The band will thus fit snugly around a tooth when applied thereto.

In use, after a tooth has been prepared and is ready for filling, a matrix band is cut to fit the tooth and assembled as shown in Figure 7. Obviously, the matrix holder is placed in the mouth of the patient so that the 'squared'end 22' may be engaged by the handle 23. We will say that the terminal end 32 of the band is to be attached to the movable block I! and to the-end 33' to the block l5. Each terminal end is passed beneath the respective bight portions 28 and respective pin of the blocks inserted in the apertures'o fthe terminal ends. The band is now applied to the tooth and by afiixing the handle 23 to th squared end and rotating the handle in a clockwise-direction simultaneous movement of the-blocks I S and I! in opposite directions will be-effected, drawing upon the terminal ends and the band proper snugly around the tooth. As may be seen in Figures 3 and 8, movement of the blocks will tend to swing the loop devices 21 in the direc-. tion of the pins due to engagement between the bight portions 28 and inner portions of the terminal ends of the band. By reason of the divergence of the pins 26 and the off center pivoting of the loop devices 27 the band will be firmly held against slippage fromth'ep'ins. Re-

verse rotation of the Worm shaft 20 will lessen the tension of the matrix band for removal from the tooth.

While I have shown and specifically described the invention, this is by way of illustration only, and I consider as my own all such modifications as fairly fall within the scope of the appended claims.

I'claim:

1. A means-for securing respective ends of a crossed matrix band upon oppositely movable blocks comprising pins in the upper face of each block diverging from each other and adapted to receive a terminal end of a matrix band thereon and a'loop device swinga'bly mounted upon each block, the bight portion thereof overlying the band and cooperable with the pin for retaining theband thereon in one direction of movement of the-blocks.

2. The structure of claim 1 in which the loop device is pivotally mounted off center with respect to the mounting of said pins.

3. In a dental matrix, the combination of a matrix band having reduced terminal endasaid band having an opening inwardly of the'ba'se of one of said ends adapted to receive the other end therethrough, each-end having an aperture, a pair of oppositely movable block members, a pin member in the upper face of each block member adapted to be insertedinre'spctiveapertures of the terminal ends of the band, manual means for simultaneously movin'g theblocks'and a loop member on each block overlying respective terminal ends of the bandand cooperative with respective pins for retention of the band-to s'aid block.

4. The structure of claim 3,- in which the pin members diverge 'in opposite directions and said loop members are pivotally mounted off center from the mounting of the pin members.

5. A matrix band retainer comprising an elongated body member having achannel formed therein, said channel having opposed parallel flanges, a block member fixed atone end of the channel, a movable block slidably interengaged between said flanges and 'within'thechannel, each of the blocks having a threaded opening aligned with the longitudinal axis of the channel, the threads of the opening of one bloclr' biiigopposite to that of the opening'of the*otlier blocl ,a worm shaft extende'd throug'h the-aligned openings and having threads complemental to respe'ce tive openingswhe'rebyto obtain reverse movements of the blocks u'p'o'n' rotationbf the worm shaft, and each of said blocks having a pin arranged in divergent relation for engagingrespe'ctive apertured ends of crossed terminals of a matrix band, and a 1001) member swingably mounted upon each block'and overlying the terminal endsof the matrixband. 7

JAMES D. MORRISON. 

